South Korean authorities have indicted four ROK nationals on charges of taking payments and orders from Pyongyang, in connection with an investigation into an alleged North Korean spy ring in the southern city of Changwon.

The Seoul Central District Prosecutors’ Office announced the indictments on Wednesday against three men and one woman for allegedly violating the country’s National Security Act. Police previously detained the suspects in late January, and they will now face trial at a yet-to-be-announced date. 

The four suspects allegedly formed an underground spy cell called the Vanguard of the People’s Independent Unificationin Changwon in 2016, operating